Propeller



Sept. 19, 1939. o. D. LITTLEJOHN 2,173,397

PROPELLER Original Filed April 14, 1935 5 Sheets-Sheet 1 25. v v 7 m m i z mw 2 mm a u z 3/ \VB u 1+ Tb M, M m

11; I "ATTORNEY P 19, 1939 o. D. LITTLEJOHN 2,173,397

PROPELLER Original Filed April 14, 1935 5 SheetS- -Sheec 2 P 1939. 0.0. LITTLEJOHN 2,173,397

PROPELLER Original Filed April 14, 1935 5 Sheets Sheet 3 m l/ENTOR ORV/HE .2 17 ZZEJUHN A TTORNE Y P 19, 1939- o. D. LITTLEJOHN 2,173,397

PROPELLER Original Filed April 14, 1935 5 Sheets-Sheet 5 ,lhveni'or.

ORVILLE D LIT HEJOHN Patented Sept. 19, 1939 UNITED STATES PATENT OFFICE Substitute for application Serial No. 74,298, April 14, 1935. This application September 1, 1937,

Serial No. 162,007

11 Claims.

This invention relates to fluid propulsion means and particularly pertains to a propeller.

It is the principal object of the present invention to provide a type of propeller which is particularly adapted for use on airplanes, ventilating apparatus, and other types of apparatus where fluids are moved, and which propeller due to its novel design will insure that a relatively large volume of fluid may be moved by it by the exertion of a relatively small amount of driving power, and which further insures that due to its novel design the blades of the propeller may be relatively short and of small dimensions as compared to propellers now used in connection with the class of apparatus with which the present invention is concerned.

The present invention contemplates the provision of a propeller having a plurality of blades and which embodies the functions of an airfoil propeller, as well as a turbine type of propeller structure, whereby the combined action of the two will cooperate in moving fluids by which the propeller is surrounded.

The invention is illustrated by way of example in the accompanying drawings in which:

Figure 1 is a view in front elevation showing one form of the present invention.

Fig. 2 is a fragmentary view in section showing the form of the end of the blade tip as seen on the line 22 of Fig. 1.

Fig. 3 is a View in transverse section through the blade structure as seen on the line 3--3 of Fig. l, and with the transverse end rib appearing in elevation.

Fig. 4 is a view showing the type of propeller disclosed in Fig. 1 in an edgewise position to more clearly disclose the blade construction.

Fig. 4a is a view of the propeller of Fig. 4 as seen on the line 4a-4a.

Fig. 5 is a view in elevation showing a form of the present invention particularly adapted for use in airplane work with low speed engines.

Fig. 6 is a view showing the propeller of Fig. 5 in an edgewise position.

Fig. is a View of the propeller of Fig. 6 as seen on the line tic-6a.

Fig. 7 is a view in front elevation showing a form of air plane propeller as particularly adapted for high speed engine use.

Fig. 8 is a view showing the propeller of Fig. '7 as viewed in an edgewise position.

Fig. 9 is a view in elevation showing a propeller particularly adapted for ventilation work.

Fig. 10 is a view of the propeller of Fig. 9, as seen in an edgewise position.

Fig. 11 is an end view of the form of a propeller shown in Fig. l, as viewed in the direction of the line l|--H of Fig. 1.

Fig. 12 is a. view in transverse section and elevation as seen on the line lZ-IZ of Fig. 1. '5

Fig. 13 is a view in transverse section and elevation as seen on the line I 3--l3 of Fig. 1.

Fig. 14 is a view in transverse section and elevation as seen on the line l4l4 of Fig. 1. v

Fig. 15 is a view in transverse section through 0 the hub of the propeller as seen on the line l5-I5 of Fig. 1.

Fig. 1A is v a view in longitudinal section through the propeller as seen on line IAIA as indicated in the direction of the arrows of Fig. 1 15 of the drawings.

Fig. 4B is a view in longitudinal sections through the propeller as indicated on line 4B-4B in the direction of the arrows of Fig. 4.

Fig. 5A is a view in end elevation as indicated on line 5A-5A in the direction of the arrows of Fig. 5 of the drawings.

Fig. 7A is a view in end elevation as indicated in line 'lA-1A of Fig. 7 in the direction of the arrows.

Fig. 7B is a View in longitudinal section through the form of the propeller as shown in Fig. 7 of the drawings.

Fig. 8A is a view in section of the propeller as seen on line 8A-8A of Fig. 8 and in the direc- 30 tion of the arrows.

Referring to the form of the invention shown in Figs. 1 to 4 of the drawings, it will be seen that a double blade propeller is provided having a centra1 hub portion ID to receive a propeller shaft 35 II and oppositely from which blades l2 and I3 extend. These blades extend in diametrically opposite directions from the hub l0 and are formed with straight opposite side edges l4 and I5 and a square end face IS. The leading edge l5 of 40 blade l3 and the trailing edge M of the blade [2 are in the same plane as shown in Fig. 4 of the drawings, and likewise the leading edge [5 of the blade I2 is in the same plane with the trailing edge I4 of the blade l3. Thus it will be seen'that 45 the blades are oppositely warped to be disposed at a desired opposite inclination to each other and opposite pitch. This is clearly shown in Fig. 4a where it will be seen that the blades l2 and 13 extend oppositely from'the hub l0, and it will also 50 be noted that each of the blades is formed with a lip I6 as shown in Fig. 4 which continues from the trailing edge [4 of one blade and to a point beyond the hub l0 and along the trailing edge 14 of the opposite blade. This lip gradually de- 55 creases in thickness toward its outer end and as shown in Fig. 3 of the drawings is formed with a. relatively sharp edge I1 and inner and outer tapered faces l8 and I9 are coincident with the edge I! at their point of juncture with the trailing edge l4 of a blade. Due to this arrangement a trough 20 occurs between the pressure face 2| of a blade and a lip l6. As shown in Fig. 3 of the drawings this trough is of greatest width at the hub l0 and converges to the point of juncture with the edge I! of the lip I6. This produces a passageway through which air may be forced from the displacement face of one blade around the hub and against the pressure face of another blade. Attention is also directed to the fact that the pressure side of the blades l2 and 13 are transversely concaved in section and that they terminate in a transversely extending rib 22 which is particularly shown in Fig. 2 of the drawings.

It is to be understood that the propeller as here shown moves counter-clockwise in a direction indicated by the arrow at in Fig. 1. When the propeller is driven in the direction indicated theair is pumped from the area in advance of the hub, and from the displacement side of the oppositeblade near the hub and driven by centrifugal action to the ends of the troughs 20 as designated at b. At the same time the air thus pumped will be compressed or squeezed in the gradually-converging throat of the trough 20 and between the inner face l8 of the flange I6 and the adjacent pressure face 2| of the blade. This air will thus be forced out of the restricted Opening of the trough 20 at b in a violent blast. At the same time the air thus forced radially blasts off at the point I) from the channel but with this blast an increased pressure is built up along a section of the pressure side of the blade from the hub throughout the length of the trough 20. All of the air picked up in this area blasts off of the blade at point I). The air in advance of the leading edge of the blade is scooped up, and before the air can escape from the advancing blade a violent pressure is created so that the radially moving stream of air from along the trough 20 and the laterally moving stream of air from along the entering face of the blade will strike with considerable Violence and will be directed in a line substantially parallel to the rotating axis of the propeller. This action is materially increased over that obtained by a propeller of the airfoil type alone, or a propeller having centrifugal vanes and passageways. The air will thus be forced from the pressure side of the propeller with great violence, and will at the same time create a suction due to the displacement of air on the suction side of the propeller to accelerate the movement of a large volume of air through the propeller.

In this particular type of propeller attention is directed to the fact that a novel action is obtained by placing the rib 22 across the end of the propeller blades. This is to retard the longitudinal movement of the air from the ends of the propeller. These ribs also insure that the air pressure will be increased from the entering edge of theblade to the trailing edge. The flange lBi'WhlQh is represented by the edge I! and the face I8 acts to retain the air which is moving .along the trough 20 so that it will not bereleased until it reaches the point b. It has also been found that the presence of the transverse rib 22 materially decreases the noiseproduced incident to the operation of the propeller or fan.

The volute curved shape of the bottom of the trough 20 insures that the air will be gradually and positively drawn from around the hub l0 and will move outwardly to encounter the air being forced rearwardly by the main body of the propeller blades. In this connection it will be seen that each propeller blade of the type shown in Figs. 1 to 4, inclusive, comprises two sections,

the section represented by the trough 20 bound on opposite sides by the flange l6, and the adjacent surface of a blade, and a second section which represents the blade portion having pressure surface 2! emerging from the bottom of the trough 2G and gradually increasing in width to a point where a longitudinally extending blade portion continues forwardly beyond the end of the flange IS.

The particular type of propeller shown in Figs. 1 to 4, inclusive, is for circulation fans and air duct work where a free delivery of air is desirable. It has also been found that the distance from the point D to the axis of the propeller is substantially one-half of the radius of the propeller. In some instances it may be desirable to use a propeller of the foregoing type as shown in Figs. 9. and 10. In this particular type of propeller the construction and action is quite similar to that of the type of propeller shown in Figs. 1 to 4, inclusive. However, the trough portion 20a which agrees with the trough portion 2110f the type of propeller shown in Figs. 1 to 4 is much flatterand the flange l6a has a substantially flat inner edge [8a forming the confining wall of the trough 290. on the pressure side of the device. The outer ends of the blades are curved and dished out at 24 in order to decrease weight in the device the portion back of the troughs 20a are cut away as indicated at 24min Fig. 9 of the drawings.

The design and action of the propeller struc ture as shown in Figs. 9 and 10, however, is substantially the same as that of the propeller shown in Figs. 1- to 4 inclusive, since both types of propellers are based upon the same fundamental theory, that being of having a turbine or pump section operating adjacent the rotary axis of the propeller, and a blade section cooperating in the zone exterior thereof. In fact, it has beenfound in some instances the portion of the blade length beyond the pump section is eliminated. and an effective fan action is still produced, since the air is forced tangentially and forwardly through the troughs 20a and between 1 the blade face and the face of the flanges [6a. In connection with such a type of fan it has been found that the disc 23 shown in Fig. 8 controls the intake or suction of the fan by closing or pocketing the turbine intake sections of the propeller. At the same time the disc 23 acts to prevent back-flow of air pressure through the entire center section of the propeller. This disc is mounted on the pressure side of the blade and its. diameter may vary for propellers to be used in different types of work. For example, for low pressure work the disc is relatively small and is increased in diameter for high pressure work or resistance. It is desirable, however, that the diameter of the disc shall in no instance be reater than one-half of the diameter of the propeller upon which it is used. In uses of the types of fans of the character shown in Figs. 5. to 10' it has been found that the presence of the disc on the fan where air is being delivered under high pressure or resistance, increases the efficiency of the fan many times over that obtained by most present types of ventilating fans, and when the same amount of power is consumed. Referring particularly to Figs. 5 to 8 of the drawings, it will be seen that two types of propellers are shown which are especially adapted for airplane work. The propeller shown in Figs. 5 and 6 comprises blades 25 and 26 which extend oppositely from diametrically opposite sides of the propeller shaft ll. This type of propeller is intended to be used on present day airplane engines, and is formed with a central hub 51 shown in Fig. 5 as having a fiat end portion bound by arcuate edges 28 and 29, and tangent edges 30 and 3!. The thickness of the propellers at its hub is greater than any present day propellers and merges into a triangular base section of the propeller blades, as shown in section view 6a. It will thus be seen that the entering edge 32 is formed at the point where Fig. 6a was taken by the intersection of a relatively flat back face 33 and an inclined displacement face 34. The blade continues outwardly and is warped to form an airfoil tip 35 which represents the Width of the blade. On the suction side of the blades the entering edge 32 merges the foil above the turbine into the warped face of the blade tips 35 and on the pressure side a face 36 occurs which is tangent to the arcuate edges 28 and 29 of the hub. This face continues beneath the pressure side of the blade ending at point 27 as in Figs. 1 to 4 to form a curved portion 31, which intersects with the warped pressure face of the blade along the line 38 indicated in Fig. 6.

Mounted upon the pressure side of the propeller of the type shown in Fig. 6 is a disc 25 which represents substantially one-half of the diameter of the entire propeller, or size that is needed; but should not exceed the one-half of the total diameter. It will be seen that in the type of device an air trough will occur on the pressure side of the blades and along the surfaces 38 beneath the warped portions of the pressure side of the blade adjacent to the channel 38. This air trough has the same function as the trough 20 previously described in reference to other figures of the drawings, and the cooperation of the extended surfaces 36 and}? will produce the same pumping action.

In the form of the drawing shown in Figs. 5 and 6 it is desirable that the driving speed be up to and including 2000 R. P. M. and when thus operated the surfaces 3'! will act to force the air radially off the propeller while moving it into a position to encounter the under inclined pressure side of the blade. The air thus forced radially will then encounter the air pressure developed under the pressure side of the blade along surfaces 36 and 31 and the propulsion of the airplane will take place. It is to be understood that the action of the displacement side of the blade is similar to airfoil action in present types of propellers as shown at 26 in Fig. 5. The disc 23 may be of a desired diameter, preferably being designed in direct relation to the speed at which the propeller is to be moved, never over one-half total diameter of propeller.

The pumping action of the propeller removes most of the air occurring in the zone from points 4! and 42 of the suction face of the propeller. This causes air displacements which creates suction in advance of the propeller. Suction is also created in advance of the points 32 and 44 along the entering edges of the blades and will act to compress and'drive rearwardly air from points 45 on the pressure side of the blade and around the disc. The suction created on the displacement side of the blade between the points 43 and 45 tends to draw the air along the front of the propeller to follow with the blasted air driven off the end of the turbine at point I) in the same turbine action as previously described. This action also increases the thrust. The thrust is created by the propeller due to the fact that the propeller rapidly moves into the displaced area. This particulartype of propeller operates more efficiently at relatively low speeds. Due to the fact that the action of the airfoil between points 43 and 45 and to the blade tips produce a fast slicing and splitting of air in front of the propeller and in the direction of travel, the airfoil blades do not permit a high R. P. M. of the propeller without causing the efficiency to fall rapidly. This is partially compensated for by the use of the center disc 23 and the turbine sections in connection therewith.

In the form of the invention shown in Figs. 7 and 8, a type of propeller is disclosed which is designed for use with high speed engines. propeller, however, from its suction side is formed with a hub 46 which has concentric arcuate faces 41 and 48. These faces extend parallel to the rotating axis of the propeller. At diametrically opposite sides of the hub portions 49 and 50 occur from which the leading edges 5! of propeller blades 52 and 53 extend. These leading edges are parallel to the trailing edge 54 of the propeller blades and upon opposite sides of the hub are continuations thereof. The propeller blades are Warped from the portions 49 and 50 to the corners of the blade tips 55 and their outer ends may be disposed substantially in the same transverse plane parallel to the back face of the propeller or at desired other angles thereto. Mounted on the back face of the propeller is a disc 23 as previously described. The back face of .the hub portion of the propeller is of greater dimensions than the front face of the hub portionand is defined by the dotted lines 5'1 and 58, as shown in Fig. 7 of the drawing, the hubs having continuing volute faces 59 and 60 which cause flanges St to occur adjacent the back face and to cooperate with the Warped faces 52 and the faces 59 and 60 to form a trough similar to that previously described in other forms of the invention. The action of this propeller is basically the same as the other propellers here shown and described.

It will be understood that the forms of propellers here shown and described may be made in different designs and may be adapted'for any purpose where it is desirable to move a fluid. In all cases the propeller will embody the use of a central section by which the air is moved radially and outer sections by which a laterally moving stream of air will encounter the radially moving stream of air to produce the results This day and instead made the scope of the .area of 75 the circle in which the propeller revolves a complete so-called airfoil over the entire'area of the circle. It is provided that in air types the higher the R. P. M. the greater percentage of total work is accomplished at the center of the propeller.

It will thus be seen that the propeller here disclosed embodies principles making it generally adaptable for all classes of work and that the action of the propeller insures that the eflicient movement of fluids will take place with a minimum expenditure of horsepower.

While I have shown the preferred form of my invention, as now known to me, it will be understood that various changes might be made in the combination, construction and arrangement of parts, by those skilled in the art, without departing from the spirit of the invention as claimed.

Having thus described my invention, what I claim and desire to secure by Letters Patent is:

1. A propeller comprising a hub section having volute faces extending from diametrically opposite sides of the hub and partially around the hub, and propeller blades extending radially from diametrically opposite sides of the hub, the bases of which blades are intersected by said volute faces.

2. A propeller comprising a hub section having volute faces extending from diametrically opposite sides of the hub and partially around the hub, and propeller blades extending radially from diametrically opposite sides of the hub, the bases of which blades are intersected by said volute faces, whereby a relatively straight face extending parallel to the rotating axis of the propeller will occur along said volute surface and will gradually decrease in area from the displacement side of the propeller to the pressure side.

3. A propeller comprising a hub section having volute faces extending from diametrically'opposite, sides of the hub and partially around the hub, propeller blades extending radially from diametrically opposite sides of the hub, the bases of which blades are intersected by said volute faces, whereby a plane face extending parallel to the rotating axis of the propeller will occur along said volute surface and will gradually decrease in area from the displacement side of the propeller to the pressure side, and a flange extending along the pressure edge of the volute face whereby the volute face will form the bottom of an air trough decreasing in area from the displacement side of the hub to a relatively narrow trough on the pressure side of the hub.

4. A propeller comprising a hub section having volute faces extending from diametrically opposite sides of the hub and partially around the hub, propeller blades extending radially from diametrically opposite sides of the hub, the bases of which blades are intersected by said volute faces, whereby a plane face extending parallel to the rotating axis of the propeller will occur along said volute surface and will gradually decrease in area from the displacement side of the propeller to the pressure side, and a flange extending along the pressure edge of the volute face whereby the volute face will form the bottom of an air trough decreasing in area from the displacement side of the hub to a relatively narrow trough on the pressure side of the hub, said blade sections being warped from the line of intersection with the volute surface of the propeller to their tips.

5. A propeller comprising a hub section having volute faces extending from diametrically opposite sides of the hub and partially around the hub, propeller blades extending radially from diametrically opposite sides of the hub, the bases of which blades are intersected by said volute faces, whereby a plane face extending parallel to the rotating axis of the propeller will occur along said volute surface and will gradually decrease in area from the displacement side of the propeller to the pressure side, a flange extending along the pressure edge of the volute face whereby the volute face will form the bottom of an air trough decreasing in area from the displacement side of the hub to a relatively narrow trough on the pressure side of the hub, said blade sections being warped from the line of intersection with the volute surface of the propeller to their tips, and a solid disc mounted on the pressure side of the propeller and being of a diameter substantially equal to the diametrical portion of the propeller as represented by the volute sections thereof.

6. A propeller having a relatively long hub as compared with the diameter of the propeller, the pressure face of said propeller being in substantially the same plane as the pressure end of the hub, volute faces extending partially around the hub from one side to the other, said volute faces being upon diametrically opposite sides of the hub, the surface of said faces being parallel to the longitudinal axis of the propeller, blades extending oppositely from said hub, the trailing edge lying substantially in the plane of the pressure face of the hub and the entering edge extending from a point adjacent the displacement face of the hub, said blades being warped and intersecting the volute faces of the hub to progressively shorten the volute faces from the displacement side of the hub to the pressure side, at which point the volute face will terminate adjacent to the trailing edge of a blade and at a point substantially midway from the rotary axis of the propeller to the tip of the blade.

7. A propeller having a relatively long hub as compared with the diameter of the propeller, the pressure face of said propeller being in substantially the same plane as the pressure end of the hub, volute faces extending partially around the hub from one side to the other, said volute faces being upon diametrically opposite sides of the hub, the surface of said faces being parallel to the longitudinal axis of the propeller, blades extending oppositely from said hub, the trailing edge lying substantially in the plane of the pressure face of the hub and the entering edge extending from a point adjacent the displacement face of the hub, said blades being warped and intersecting the volute faces of the hub to progressively shorten the volute faces from the displacement side of the hub to the pressure side at which point the volute face will terminate adjacent to the trailing edge of a blade and at a point substantially midway from the rotary axis of the propeller to the tip of the blade, and a flange formed as a continuation of the trailing edge of one blade and extending along the pressure edge of the volute surface adjacent the opposite blade whereby an air trough will extend from around the hub in advance of the trailing edge of the first named blade to a point along the length of the trailing edge of the second named blade.

8. A propeller having a relatively long hub as compared with the diameter of the propeller, the pressure face of said propeller being in substantially the same plane as the presures end of the hub, volute faces extending partially around the hub from one side to the other, said volute faces being upon diametrically opposite sides of the hub, the surface of said faces being parallel to the longitudinal axis of the propeller, blades extending oppositely from said hub, the trailing edge lying substantially in the plane of the pressure face of the hub and the entering edge extending from a point adjacent the displacement face of the hub, said blades being warped and intersecting the volute faces of the hub to progressively shorten the volute faces from the displacement side of the hub to the pressure side at which point the volute face will terminate adjacent to the trailing edge of a blade and at a point substantially midway from the rotary axis of the propeller to the tip of the blade, and a flange formed as a continuation of the trailing edge of one blade and extending along the pressure edge of the volute surface adjacent the opposite blade whereby an air trough will extend from around the hub in advance of the trailing edge of the first named blade to a point along the length of the trailing edge of the second named blade, the edges of said blades being warped to form an airfoil.

9. A propeller comprising a hub section having volute faces extending from diametrically opposite sides of the hub portion, the transverse plane of said faces being parallel to the rotary axis of the propeller, the volute portions being of width equal to that of the hub and tapering from the displacement side of the hub to the pressure side,

blades extending outwardly from the hub and the propeller being greater than one-half the diameter of the propeller.

10. A propeller comprising a hub section having volute faces extending from diametrically opposite sides of the hubportion, the transverse plane of said faces being parallel to the rotary axis of the propeller, the volute portions being of width equal to the length of the hub at the hub and tapering from the displacement side of the hub to the pressure side, blades extending outwardly from the hub and the volute portions the diameter of the volute portion of the propeller being greater than one-half the diameter of the propeller, and the opposite edges of the blades being straight and parallel and terminating in square end portions.

11. A propeller comprising a hub section having volute faces extending from diametrically opposite sides of the hub portion, the transverse plane of said faces being parallel to the rotary axis of the propeller, the volute portions being of width equal to the length of the hub at the hub and tapering from the displacement side of the hub to the pressure side, blades extending outwardly from the hub and the volute portions the diameter of the volute portion of the propeller being greater than one-half the diameter of the propeller, and the opposite edges of the blades being straight and parallel and terminating in square end portions, and a transverse rib formed across said end portions on the inner faces thereof.

ORVILLE D. LITTLEJOHN. 

